RF System Technician
Company is seeking a mature, experience person with a dynamic personality and a STRONG RF & IT background.
The job opening involves daily service of large Motorola Fix Network Systems. The ideal candidate will have a FCC license,
ETA , MCSE, CISCO certifications, and have recent work experience with SMARTNET, SMARTZONE, ASTRO P25 Trunking Systems or
equivalent technologies. This includes all ancillary equipment associated with large public safety trunked radio systems
(console work stations, data, servers, routers, switches, etc.).
Comdel for Support
Comdel designs and manufactures RF and DC power
supplies and process instruments for the semiconductor, solar cell/photovoltaics, flat panel, and industrial heating industries.
Comdel products are in use worldwide by the industry's major equipment and IC fab manufacturers.
We take wireless communications for granted.
Just as people my age thought pocket-size transistor radios that ran on 9V batteries were always available, today's kids
give no thought to whether there was a time when everyone did not carry a cellphone around. FM radio, if listened to at
all nowadays, is likely either via an Internet connection or via an embedded FM radio IC in his/her phone, with ear bud
wires acting as an antenna. It is obviously no big deal, since it always was so. In the early part of the last century most
people did not own any sort of radio - even a commercial AM broadcast receiver. Having something as mysterious as a shortwave
'rig' was an indication of technical prowess since many operators built their own equipment from kits or schematics. Participation
in amateur worldwide was huge at the time, which is amazing given the amount of work required to set up even a relatively
simple CW (Morse code) setup...
Not everyone is into radio history,
so items like this advertisement for Spartan Radio's Model 60 Short-Wave Receiver (April 1932 QST) will not invoke much or any interest.
On the other hand, there is a large contingent of hobbyists and professionals who enjoy seeing these snapshots of the places
from whence we have come technically. Products like radios, kitchen appliances, automobiles, etc., were constructed very
robustly with metal, wood, and fabric. No cheap plastic will be found anywhere, but maybe not for the reason you think -
plastic as we know it today had not entered the commercial marketplace yet. In fact, many 'modern' plastic formulas and
processes were a closely held military secrets until the end of World War II.
Although written in 1933
(era of the Great Depression), this article on the autodyne receiver has a good discussion
of noise sources and how to trade off amplification for signal intelligibility. It originally used the De Forest Audion
vacuum tube amplifier. Noise figure and noise temperature were not commonly used at the time, but the concept is encompassed
in the treatment. So, what is an autodyne? It is a form of regenerative circuit that, rather than being tuned right at the signal of interest,
is tuned slightly off center. It functions as a sort of combined local oscillator and amplifier for demodulating CW (Morse
code) signals. Technical writing styles have not changed much over the decades, even as the terminology has.
I like these kinds of charts. In this
case it is a map of all the Internet connected devices in the world, or at least per the 2.7 billion IP addresses
(310 million replies) that computer security guru HD Moore pinged to get data for his map. On his off time as a researcher
at Rapid7, he uses an arsenal of computers at home to run such experiments.
Says Moore, "I have a lot of cooling equipment to make sure my house doesn't catch on fire." Part of the goal was to determine
how many people never changed the default password for their modems and other gateway devices. It was a lot. Although everything
he did was legal, he did get complaints from some of the pinged. Do you still have the default password on your wireless
router? I just checked a few of my neighbors' WiFi connections
and didn't find any with 'default' as the password.
Samsung's GALAXY S 4
Skyworks Solutions today announced it is supporting Samsung's GALAXY S 4 smartphone platforms with multiple
high-performance analog and front-end solutions. “Skyworks is delighted to be supporting Samsung's flagship GALAXY S 4 smartphone
platform,” said Liam K. Griffin, executive vice president and corporate general manager at Skyworks. "Given our broad
product portfolio and system-level expertise, we have expanded our partnership with Samsung beyond delivering traditional
power amplifiers to providing an entire suite of solutions for an unprecedented level of analog and RF integration"
If you have been
in the RF and microwaves business for any length of time, you are probably familiar with a company named Varian. In the
days before you did your parts shopping online, Varian catalogs populated the desks and bookshelves of many RF engineers
who worked in the radar field, including mine. Did you know that it is named after the brothers Russell and Sigurd Varian,
who started the business in 1948 to market their high power
klystron tubes? Following a number of reorganizations, it was purchased by Agilent technologies in 2010.
This story from Radio Electronics magazine does a real nice job explaining the workings of a klystron without getting
too deep into the gory theoretical detail.
for Long-Time Support
Pulsar Microwave is celebrating its 26th anniversary
as a valued supplier of passive microwave components covering
the frequency range of 10 kHz to 40 GHz with both narrow band and ultra-broadband products for the wireless communications
markets. Power dividers, couplers, attenuators, phase shifters, switches, and more.
O-scopes w/Logic Analysis
With the introduction of
the new R&S RTM series, Rohde & Schwarz has expanded the functional range of its
bench oscilloscopes. The key upgrades are a 20 Msample deep memory and a logic analysis option with
16 digital channels. The smart operating concept of the new R&S RTM models ensures extreme ease of use. The R&S
RTM provides time domain, logic, protocol and frequency analysis functions in a single box, making it the ideal instrument
for the testing and development of electronic circuits
"As your company grows,
you'll progress through the three phases of Internet customer feedback: 1. not enough; 2. just the right amount; and 3.
way, way too much. I'm joking, of course. There is no Phase Two." -
co-founder and CEO of evernote.
PMI Model No. is a limiting amplifier that operates
over the frequency range of 300 MHz to 2.5 GHz. This model provides a gain of 85 dB typically and a limited
output of +15dBm ± 2.5 dBm. The typical noise figure is 5 dB and a maximum VSWR of 2.0:1 is maintained under all
operating conditions into a 50 ohm impedance. The operating voltage is +12 VDC and the amplifier is reverse voltage
protected. The DC current is 485 mA typically.
George Wilmer is a radio frequency (RF), electromagnetic compatibility (EMC), and systems
engineer experienced in design, integration, test, and board level to system level architecture. Staff engineering positions
and independent contracting with some of the country's largest technology corporations have provided valuable insight into
a variety of challenges and hands-on opportunities to resolve complex issues. Please contact George if you have need of
such a fellow.
Microwave Product Digest
Here are a few great articles that might interest you. They all appeared in Microwave Product Digest.
- Detecting PIM Problems
in Antenna Systems and Discovering the Latest Remedies, by David Strand
- RF Beamforming Techniques
Improve TD-LTE Cell-Edge Performance, by Craig Grimley
- Frequency Multiplication
Techniques, by Ramon Cerda
Sad Moment for the FCC, by Barry Manz
for April 28, 2013
Take a break from the
drudgery by trying your hand at some of these goodies. Every word in the
RF Cafe crossword puzzles is specifically
related to engineering, mathematics, and science. There are no generic backfill words like many other puzzles give you,
so you'll never see a clue asking for the name of a movie star or a mountain on the Russia-China border.
Celestron CPC800 Deluxe
The sky finally cleared and the wind finally calmed
down enough to try out my new solar filter on my Celestron CPC800 Deluxe telescope ...by the time the sky cleared the sun was only
about 30 degrees above the western horizon, so the seeing quality was not so great. Still, the view through the eyepiece
was awesome when the atmosphere steadied occasionally for a split second. It was good enough to prompt me to go ahead and
hook up the Celestron NexImage 5 camera. ...The large image of the entire solar disk was made by simply holding a point-and-shoot
type camera up to the 32 mm eyepiece ...I figured the best chance of obtaining a good image was to use the video function
of the NexImage 5 and run the results through RegiStax software...
Life was good as Elrond, Lord of
Rivendell, but ever since being defeated by Neo, Agent Smith has evidently been having a hard time finding work. Now reduced
to doing a gig pitching medical equipment for GE, maybe Agent Smith has had a change of heart from when he believed, "Human
beings are a disease, a cancer of this planet. You're a plague and we are the cure." It's a great commercial...
Parties Aren't Like Your Parties
You might remember a few
years back when Intel started producing commercials for geeks. The first was "Our Rock Stars Aren't Like Your Rock Stars," featuring
USB co-inventor Ajay Bhatt. Not all of their videos have been spectacular, but this newer one is titled "Our Parties Aren't Like
Your Parties" had me ROTFLMAO.
As an erstwhile avid philatelist,
I am always pleased to see countries issue postage
stamps that commemorate advances in technology and the people who play key roles in that advancement. South Korea recently
announced a set of four stamp designs that feature
smartphones. It was part of their April 22, 2013 Information and Communication Day celebration. Here is a page I created
for stamps featuring radio and radar.
consistently has some of the best graphs and illustrations of any technical magazine, but this new one from
IEEE Spectrum that displays broadband data connectivity for wired vs. wireless is right up there in
quality IMHO. What distinguishes a good chart from a bad chart? Assuming that all pertinent data is presented, the most
important feature is eye catchiness. If an audience is not attracted to your information, you have wasted time. Sure, science
purists will argue that a B&W line graph is all that is required to convey important results, but in today's world expectations
are higher than, say, in 1879 when Thomas
Edison might have been giving a lecture on the performance of various compositions of lamp filaments. Cluttering a chart
with superfluous information such as background photos is not only unnecessary but potentially damaging; however, judicial
use of color, line styles, and font faces can make the difference between success and failure.
Internet Sales Tax?
You have probably heard and/or
seen the scuttlebutt about Congress trying to push through an
Internet sales tax, ostensibly in order
to level the playing field for brick and mortar businesses versus online businesses. You can be sure the effort has nothing
to do with fairness and everything to do with politicians' insatiable appetite for tax money. They have been salivating
over the possibility of reaping that new revenue source for years. The plan is to require online sales from out-of-state
buyers to have sales tax collected and remitted to the appropriate state revenue department. Local businesses are per the
claim disadvantaged because they must collect their home state's sales tax, which supposedly causes buyers to prefer Internet
vendors in order to avoid such taxes. As one who has purchased many items over the Internet in the last 15 years, I can't
think of many times when avoiding sales tax was the prime motivation for my decision. It was usually because either the
item I wanted was not...
the Total Eclipse of the Sun
Amateur radio operators, as with hobbyist participants in many other realms, historically
have contributed significantly to the efforts of their professional counterparts. I have written of it often. This particular
instance is where signal measurements in the Ham bands during a total eclipse of the sun were used to assist scientists
debating the merits of rival theories relating to origin of ionization in the
Layers of the E and F regions, both of which were proposed in 1902 (yes, the Heaviside of step
function fame). Long distance (DX) communications are dependent upon such ionization
to reflect radio signals that would otherwise pass through the atmosphere and into space. The test at hand would settle
the argument since the one should fail if ionization was unaffected during totality. Read the article
(or skip to the end) to discover which gentleman's theory won the day.
You have probably heard and/or seen the scuttlebutt about Congress trying to push through an Internet sales tax, ostensibly
in order to level the playing field for brick and mortar businesses. You can be sure the effort has nothing to do with fairness
and everything to do with politicians' insatiable appetite for tax
money. The plan is to require online sales from out-of-state buyers to have sales tax collected and remitted to the
appropriate state revenue department.
Voice Recording Restored
Alexander Graham Bell's voice
has been heard for the first time thanks to a team of scientists that restored one of his
wax-and-cardboard disc recordings from April 15, 1885.
On it he speaks, "In witness whereof - hear my voice, Alexander Graham Bell."
DC to Microwave Frequencies
AWR's new application
note titled, 'Multisim/Ultiboard
for Low-Frequency Simulation and Layout' details how to complement
Microwave Office® circuit design software
with National Instrument's Multisim circuit simulation software
and Ultiboard printed circuit board (PCB) layout software for
a comprehensive design flow spanning from DC to microwave frequencies.
Optical Antennas, by Agio, Andrea Alù. This consistent and systematic review
of recent advances in optical antenna theory and practice brings together
leading experts in the fields of electrical engineering, nano-optics and nano-photonics, physical chemistry and nanofabrication.
Fundamental concepts and functionalities relevant to optical antennas are explained, together with key principles for optical
antenna modeling, design and characterisation. Recognizing the tremendous potential of this technology, practical applications
are also outlined. Presenting a clear translation of the concepts of radio antenna design, near-field optics and field-enhanced
spectroscopy into optical antennas, this interdisciplinary book is an indispensable resource for researchers and graduate
students in engineering, optics and photonics, physics and chemistry.
Technologies for Support
Copper Mountain Technologies makes lab-quality virtual vector network analyzers with high accuracy, wide dynamic range,
a familiar UI and a broad variety of standard and customizable features in frequency ranges from 300 kHz to 8 GHz.
Where did the name come from? Read here (near page bottom).
It is mainly advertisers
that keep RF Cafe on the air, so to speak, to many thanks to SigaTek. SigaTek specializes in high quality,
high frequency microwave communication components up to 60 GHz. As
a pioneer supplier of microwave RF components, the main products include directional couplers, bias tees networks, power
dividers/combiners, 3 dB hybrids 90° and 180°, microwave mixers, frequency doublers, load terminations, and coaxial
connectors and adapters.
Some of what you and I consider common knowledge is largely unrealized by most people.
Call me a geek, but I take pleasure in pointing out to people that the Fahrenheit and Centigrade scales are equal at -40°,
and I especially enjoy working out the simple proof for them. Most people appreciated the effort and are amazed, claiming
to have never seen that before. When I read the following in Smithsonian magazine, "Winter temperatures here, some
250 miles northeast of St. Petersburg, sometimes plunge to minus 40 degrees Fahrenheit," I wondered whether the author knew
that -40°F = -40°C.
Maybe he just didn't want to confuse his readers by omitting the redundant superfluous 'F' or 'C,' and it couldn't be 'K'
because there are no negative Kelvin degrees. It could also be that he knew but figured...
Noise Dielectric Resonator VCO
Z-Communications' new high performance
DRO8000A covers 8000 MHz within a tuning voltage
range of 0-12 Vdc and is ideal for the test and measurement market. Utilizing dielectric resonator technology this
VCO features a typical phase noise of -103 dBc/Hz @ 10 kHz offset and an average tuning sensitivity of only 1 MHz/V.
Design News' 'Sherlock Ohms' mysteries are submitted by their readers. They tell stories of electronics posers and
how the e-sleuths solve them. I only link to ones that RF Cafe visitors might enjoy. This one is a good reminder of
unintended consequences of outdated government regulations
and how fear of nonconformance can in and of itself result in nonconformance.
NuWaves Engineering, an international Radio Frequency (RF) and
Embedded Systems solutions provider, announced today that it has added Lighthouse Technical Sales, LLC as a representative
of its commercial off-the-shelf (COTS) RF module-level products and engineering design services for the New England region
of the United States. With the signing, Lighthouse brings NuWaves nearly 75 combined years of successful OEM sales in RF,
interconnects, fiber optics, and other high-technology electronic products to NuWaves' expanding domestic sales representative
Joins Our Honored List
Manley Head as the newest addition to our ever-growing list
of former USAF radar technicians. Per Manley, "I read the article about the GCA radar and it took me back to the days that
I was a radar technician on the original
MPN-1 GCA from about 1956-1959 in San Angelo, TX and in Harlingen, TX. The unit in the picture does not
look quite like what I remember about the exterior. The antennas seem different from my ancient memory. However, the truck
showing in the picture had a big 'Buddha' diesel generator in it that we had to start up once in a while. We had to bleed
the fuel lines while it was running to get the air out. Odd how such such details stick in my memory."
for Continued Support!
"Our goal at vidaRF is to design and manufacture a reliable and cost-effective RF / microwave component that fits each customer's individual application. We have the capability
to produce large volume as well as quick turnaround for your custom designs. We will provide the highest standards
of quality products, competitive prices, quick turnaround and exceptional customer service. We engineer unique simple
solutions for defense, multimedia, medical, datacom, telecom, and industrial markets."
EDN website's Senior Technical Editor Charles
Murray posted an interesting piece on well-known people who you might not have realized were
engineers. U.S. presidents Herbert Hoover and Jimmah Cahtah[sic] are amongst
them. Not on the list are
Rowan Atkinson and Brian May,
guitarist of the band Queen, has a PhD in astrophysics
(although that's not engineering).
Here is a great treatise
waveguide theory put in layman's language. Although written in 1948 at a time when microwave frequencies
were just coming into common use, the language and descriptive drawings are similar to what you will find in modern textbooks.
Waveguide is not practical for use at lower frequencies because the physical dimensions prohibitively large. For instance,
for the FM radio band (88-108 MHz), waveguide width for a TE10 cutoff frequency
at 88 MHz is around 67.5 inches. According to Wikipedia, the first waveguide was proposed by J. J. Thomson in
1893 and experimentally verified by Oliver Lodge in 1894.
How much do you pay every month for
all of your personal communications? That
includes, but is not limited to, smartphones with data plans, land lines, Internet, cable TV or satellite TV, wireless tablets
and computers. Life in 2013 practically requires some degree of connectivity, but many people are paying for way more of
it than necessary. I absolutely need a high speed Internet connection because of publishing RF Cafe
(14 Mbps for $44.90 per month). Since most of my personal communications are via e-mail,
phone service is not a high priority so my cell phone is a TracFone that I pay under $100 per year to use
(mainly when away from home). Since there is no time for TV, any watching is done via the
Internet - it doesn't matter if shows are a week or month old - so no cost there. I like using an old-fashioned telephone
with a handset at home, so a landline is also used. Up until a couple months ago I was paying the local phone company $27
per month for basic local service (no long distance, caller ID, messaging, etc.)...
"David Ortiz spoke from the
heart at today's Red Sox game. I stand with Big Papi and the people of Boston." - FCC Chairman
Julius Genachowski tweet. So, the FCC has
now endorsed dropping the F-bomb over public airwaves. You can be excused for just about anything these days if you're the
BRL Test is continuing its support to help deliver this
website to you. Please keep them in mind when shopping for new or reconditioned test equipment. They also have a newer service
specifically focusing on spectrum, network, and communication analyzer repair and calibration -
BRL Test Analyzer Repair.
Well, to be honest they're not completely free. You do need to fill out an application, so some of your time is required.
Otherwise, though, the publishers pay the cost.
Ultracapacitor Apps in Power Electronic
EE Times Europe
Asia Electronics Industry
Wireless Design & Development
in a Multielement Quad
quad antennas are as popular today as they were in 1967 when this article appeared in the ARRL's QST magazine.
That is not to say they are common. This particular design is for the 10-, 15-, and 20-meters bands, all three of which
are still in use today. If you build a
quad as shown here, you might want to find a substitute for the bamboo frame members; aluminum tubing is pretty cheap,
but if you use metal, you'll need to use insulators at the connection points. Formulas are provided for determining element
lengths and director and reflector spacings if you want to design to an alternate specific frequency or band.
Color Code Charts
time marches on and electronics components get smaller and smaller, there is no just no room to apply color code markings
for values, but in a lot of instances there is not even room to apply a laser alphanumerical marking
(at least not one large enough to be seen with an unaided eye). This goes for common passive
components like capacitors, inductors, and resistors as well as for integrated circuits, RF couplers and power dividers,
diodes, and transformers. Open your cell phone and try to find a useful component designation. Only the largest parts will
have anything you can look up on the Internet. There are ways to hunt down identification for some of the parts, but at
least for Rs, Ls, and Cs, the only way to discover a value without the assistance of a schematic is to measure it. If you
look at older electronics equipment, you will immediately notice
color stripes and/or dots on many components. The tables below will help you decipher the meanings for
component value, tolerance, temperature coefficients, etc. ,as applicable.
Many thanks to Anatech Electronics for continuing
their support of RF Cafe. Anatech Electronics designs and manufactures the industry's widest range of RF and microwave filters
at frequencies up to 40 GHz, as well as power dividers, directional couplers, and many other product types. Specialize
in standard and custom designs for commercial wireless, public safety, satcom, and defense applications.
Crossword for 4-21-2013
Every Sunday I create a
crossword puzzle using a word list
that I personally created and added to during over a decade of making puzzles. All of the words are related to engineering,
science, mathematics, chemistry, astronomy, etc. There are no numbnut clues about movie stars or clothing designers. Enjoy.